28+4 baby is measuring BIG!

Just left the doctor and she isn't worried but I am! I'm not even 29 weeks and my baby girl is measuring 3 pounds 4 ounces! Average for 29 weeks is 2.54 pounds. My doctor said 'She is healthy and her weight is good' but I'm terrified I'll give birth to a toddler! This is my sixth baby and my smallest was 6lb 12oz and my biggest was 8lb 7oz. I had a lot of problems trying to deliver my 8 pound baby and I'm so scarred I won't be able to do it again, or what if she's bigger than that?! Advice? Words of wisdom? Anything to make this mama feel better?